Apparatus and method for sensing event in smart plug device

ABSTRACT

The present invention relates to an apparatus and a method for sensing an event occurring from a target device in a smart plug installed on a supply route of power applied to the target device. To this end, a power measurement unit which comprises the smart plug measures power supplied to the target device, and an event determination unit predicts an event occurring from the target device on the basis of a power signal characteristic of the supplied power measured by the power measurement unit. The power signal characteristic indicates a variation characteristic of the supplied power caused by the occurrence of the event on the basis of supplied power before the event occurs from the target device.

PRIORITY

This application is a National Phase Entry of PCT InternationalApplication No. PCT/KR2014/010932, which was filed on Nov. 13, 2014, andclaims a priority to Korean Patent Application No. 10-2013-0137568,which was filed on Nov. 13, 2013, the contents of which are incorporatedherein by reference.

DETAILED DESCRIPTION OF THE INVENTION

Technical Field

The present disclosure relates to an apparatus and method for detectingan event occurring in a target device by a smart plug installed on asupply route of power applied to the target device.

Background Art

A home network system supports interworking between home electronicproducts based on a variety of short-range wireless communicationtechnologies.

Due to the development of smart devices capable of exchanginginformation with other devices using the communication function, thehome network system has evolved into a smart home network system capableof collecting information about component devices. It is possible forthe smart home network system to provide a new value, owing to theinterworking between smart devices.

However, since the smart devices widely used at home include just thetelevision or so, it is not free to expand the usage scenario of thesmart home network system. As a result, there is a need for the ideasthat can be used in a ‘home automation system’ utilizing the legacyproducts, which is in an earlier stage of the smart home network system.

The home automation system supports a monitoring function and a controlfunction, as its basic functions. The home automation system may bebuilt by using legacy devices. At least one sensor may be attached orinstalled to/on the legacy devices used to build the home automationsystem. The legacy device may monitor an individual operation of anadjacent legacy device, using the at least one attached or installedsensor. The legacy device may transfer information generated bydetection of the adjacent legacy device to an information collectiondevice provided on the outside. As a result, the legacy device mayinterwork with the device provided on the outside. The informationcollection device may provide the information collected from a pluralityof legacy devices to the user or the third parties.

For example, an additional sensor may be installed on the refrigeratordoor and open/close of the refrigerator door may be monitored throughthe installed additional sensor, to provide the information collected bythe monitoring to the user.

As described above, in order to monitor various events (detailedoperations) occurring in each legacy device constituting the homeautomation system, it is necessary to attach or install individualsensors suitable to monitor the features of the events.

DISCLOSURE Technical Problem

In order for the home automation system to monitor an event occurring ineach legacy device, individual sensors should be attached or installed.However, in order to increase the utilization of the home automationsystem, it is necessary to increase the utilization such as monitoringan event occurring in each legacy device, without the addition of thesensors.

An embodiment to be offered in the present disclosure provides a smartplug that monitors an event occurring in an electronic device receivingthe operating power supplied from the outside, without addition orinstallation of additional sensors.

Further, an embodiment to be offered in the present disclosure providesa smart plug that monitors an event occurring in an electronic devicereceiving the operating power supplied from the outside, regardless ofthe features of the device such as the type, model and capacity.

Further, an embodiment to be offered in the present disclosure providesan apparatus and method for recognizing occurrence of an event for anoperation of a target device in a smart plug installed on a routesupplying power to the target device.

Further, an embodiment to be offered in the present disclosure providesan apparatus and method for predicting, by a smart plug, occurrence ofan event in a target device by monitoring a change in power supplied tothe target device.

Further, an embodiment to be offered in the present disclosure providesan apparatus and method for monitoring, by a smart plug, occurrence ofan event in a target device based on the power signal characteristic ofpower supplied to the target device.

Further, an embodiment to be offered in the present disclosure providesan apparatus and method for monitoring, by a smart plug, occurrence ofan event in a target device by utilizing a power factor defining a ratioof real power to apparent power of the target device.

Further, an embodiment to be offered in the present disclosure providesan apparatus and method for setting, by a smart plug, at least onethreshold for recognizing occurrence of the same event, when a targetdevice operates in a specific operation mode and does not operate in thespecific operation mode.

Technical Solution

In accordance with an aspect of exemplary embodiments of the presentdisclosure, there is provided a smart plug device installed on a powersupply route to a target device to detect an event occurring in thetarget device. The device includes a power measurement unit configuredto measure power supplied to the target device; and an eventdetermination unit configured to predict an event occurring in thetarget device based on a power signal characteristic of the suppliedpower measured by the power measurement unit. The power signalcharacteristic represents a change characteristic of the supplied powercaused by the occurrence of the event based on the supplied power beforethe event occurs in the target device.

In accordance with another aspect of exemplary embodiments of thepresent disclosure, there is provided a method for detecting an eventoccurring in a target device by a smart plug device installed on a powersupply route to the target device. The method includes measuring powersupplied to the target device; and predicting an event occurring in thetarget device based on a power signal characteristic of the measuredsupplied power. The power signal characteristic represents a changecharacteristic of the supplied power caused by the occurrence of theevent based on the supplied power before the event occurs in the targetdevice.

Advantageous Effects

The present disclosure can make it possible to recognize an eventoccurring in a target device by monitoring power consumption of thetarget device using a smart plug, without installation of an additionalsensor. In addition, the present disclosure provides the compatibilitycapable of monitoring an event occurring in all electronic devicesregardless of the type, model and capacity of the target device.

Other effects that can be obtained or estimated by an embodiment of thepresent disclosure will be disclosed directly or implicitly in adetailed description of an embodiment of the present disclosure. Inother words, various effects estimated according to an embodiment of thepresent disclosure will be disclosed in the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows exemplary installation of smart plugs according to anembodiment of the present disclosure;

FIG. 2 shows a perspective view of a smart plug according to anembodiment of the present disclosure;

FIG. 3 shows an example of a block configuration of a smart plugaccording to an embodiment of the present disclosure;

FIG. 4 shows another example of a block configuration of a smart plugaccording to an embodiment of the present disclosure;

FIG. 5 shows a block configuration of an event determination unitconstituting a smart plug according to an embodiment of the presentdisclosure;

FIG. 6 shows a control flow for recognizing occurrence of an event in atarget device by a smart plug according to an embodiment of the presentdisclosure;

FIG. 7 shows a control flow for determining occurrence of an event in atarget device by a smart plug according to an embodiment of the presentdisclosure;

FIG. 8 shows an operation of a subroutine for determining occurrence ofan event in a refrigerator by a smart plug according to an embodiment ofthe present disclosure;

FIG. 9 shows a relationship among real power [P], reactive power [Q] andapparent power [S];

FIG. 10 shows an example in which there is no phase difference between avoltage waveform and a current waveform;

FIG. 11 shows an example in which a phase difference between a voltagewaveform and a current waveform is 90°;

FIG. 12 shows an example of a power profile to be applied for anembodiment of the present disclosure;

FIG. 13 shows an example of setting a first high threshold and a secondhigh threshold when a compressor is not operating, according to anembodiment of the present disclosure; and

FIG. 14 shows an example of setting a first low threshold and a secondlow threshold when a compressor is operating, according to an embodimentof the present disclosure.

BEST MODE

A representative embodiment for accomplishing the above-describedtechnical tasks will be disclosed in the following detailed description.The names of entities defined for the convenience of the description maybe used in the same way in the detailed description. However, the namesused for the convenience of the description are not to limit the rights.Of course, the same or simple changes thereof may be applied to thesystem having the similar technical background.

In addition, if it is determined that a detailed description of theknown functions or configurations may unnecessarily obscure the proposedtechnical points in the following detailed description, the detaileddescription will be omitted.

Various embodiments to be described below will suggest a way to detectan event occurring in a target device using thresholds set by a smartplug installed between a power supply source and the target deviceoperating by the supplied power. The thresholds may be used to detect anevent by detecting a change in the power consumption due to theoccurrence of an event. The thresholds may include at least one positivethreshold and at least one negative threshold. The at least one positivethreshold is a threshold that is set to detect an increase in the powerconsumption due to the occurrence of an event. The at least one negativethreshold is a threshold that is set to detect a decrease in the powerconsumption due to the occurrence of an event.

Even for the same event, the increase or decrease in the powerconsumption may be different depending on the operation state of thetarget device. In this case, it is possible to set at least one positivethreshold and at least one negative threshold for each operation stateof the target device.

For example, it is possible to define a positive power detectioninterval for recognizing the power consumption that increases due to theoccurrence of a specific event regardless of the operation state of thetarget device. The positive power detection interval may be set by onepositive high threshold (hereinafter, referred to as “first highthreshold”) and one positive low threshold (hereinafter, referred to as“first low threshold”). In this case, the positive power detectioninterval may be set by an interval between one first high threshold andone first low threshold.

It is possible to define a negative power detection interval forrecognizing the power consumption that decreases due to the occurrenceof a specific event regardless of the operation state of the targetdevice. The negative power detection interval may be set by one negativehigh threshold (hereinafter, referred to as “second high threshold”) andone negative low threshold (hereinafter, referred to as “second lowthreshold”). In this case, the negative power detection interval may beset by an interval between one second high threshold and one second lowthreshold.

The first high threshold and the second high threshold may be set basedon a difference between real power and a bias of the real power at thetime that an event occurs while a specific operation is not beingperformed in the target device. The first low threshold and the secondlow threshold may be set based on the biggest noise value or the averagenoise value after storing positive noises and negative noises occurringfor a predetermined time and removing a predetermined outlier in theorder of the large absolute value of the stored noises while a specificoperation is being performed in the target device.

In the following detailed description, an exemplary embodiment will beproposed, in which a smart plug is configured to determineoccurrence/non-occurrence of an event using a power factor and presetthresholds. The power factor may be defined by a ratio of real power toapparent power, at which the smart plug monitors the amount of powersupplied from the power supply source to the target device, and which isidentified through the monitoring.

Embodiments to be offered in the present disclosure will be describedbelow in detail with reference to the accompanying drawings.

FIG. 1 shows exemplary installation of smart plugs according to anembodiment of the present disclosure.

Referring to FIG. 1, a smart plug module 120 may include one or aplurality of smart plugs 120-1 to 120-n. The number of smart plugsconstituting the smart plug module 120 may be determined as the number(or more) of target devices receiving the operating power supplied froma power supply source 110. For example, the smart plug module 120 may beinstalled to bind the outlet mounted on the wall with the power cords ofthe target devices 130.

For the one or a plurality of smart plugs 120-1 to 120-n, each or someof them, not one module, may be configured independently. In thefollowing description, it is assumed that each of the one or a pluralityof smart plugs 120-1 to 120-n is installed independently. However, theproposed embodiments may not be necessarily applied to the independentlyinstalled smart plugs.

Each of the plurality of smart plugs 120-1 to 120-n is installed on aroute via which the operating power is supplied to the target devices130-1 to 130-n by the power supply source 110. In other words, the smartplug #1 120-1 is located on a route via which the power is supplied tothe target device #1 130-1 by the power supply source 110, and the smartplug #n 120-n is located on a route via which the power is supplied tothe target device #n 130-n by the power supply source 110. For example,each of the smart plugs 120-1 to 120-n may be installed to bind theoutlet mounted on the wall with the power cord for each of the targetdevices 130-1 to 130-n. The outlet mounted on the wall may be the powersupply source 110.

The target devices 130-1 to 130-n may use, as the operating power, thepower that is supplied from the power supply source 110 through thesmart plugs 120-1 to 120-n. In the following description, a smart plug120 will be used to represent each of the smart plugs 120-1 to 120-n,and a target device 130 will be used to represent each of the targetdevices 130-1 to 130-n.

The smart plug 120 is designed to monitor and control the powerconsumption of individual appliances, i.e., the target device 130. Thesmart plug 120 may set thresholds using the power profile obtained byanalyzing the power consumed in the target device 130. The thresholdswill be used for monitoring a specific event occurring in the targetdevice 130. The power profile may be defined for each type of the targetdevice. Even if the target device is the same type of device, the powerprofile may be independently defined considering the difference in thebrand and the capacity. The reason is because a change in real power maybe different depending on the type, brand and capacity of the targetdevice. The expression that the change in real power is different meansthat the characteristic of the power profile may be different.

The smart plug 120 monitors the occurrence of a specific event in thetarget device 130. For example, the smart plug 120 may monitor theoccurrence of a specific event based on an index (e.g., a power factor)indicating a change in supplied power, and preset thresholds. In orderto obtain an index indicating a change in supplied power, the smart plug120 may monitor the power supplied to the target device 130. The smartplug 120 may monitor the occurrence of a specific event in the targetdevice 130, without requiring installation of a separate sensor.

The specific event may be an event for the operation provided by thetarget device 130. For example, the specific event may be open/close ofa refrigerator door, switching of the TV channel, the current operatingstate (washing, rising, dehydration, etc.) of the washing machine, andclogging of the vacuum cleaner.

In the preferred embodiment to be described below, an example of anoperation for detecting occurrence/non-occurrence of an event for theopen/close of the refrigerator door will be considered. The smart plugdetects the open or close of the refrigerator door using thepre-designed power profile for the refrigerator. In this case, it wouldbe preferable to create the power profile, given that the change in realpower may be different depending on the brand and capacity of therefrigerator. This can be utilized for determining the safety of elderlypeople living alone, and managing the regular eating habits thereof.

FIG. 2 shows a perspective view of a smart plug according to anembodiment of the present disclosure.

Referring to FIG. 2, an insertion terminal 210 to be inserted into theoutlet is provided on the rear of the smart plug, and a binding terminal220, into which the power cord of the target device is to be inserted,is provided on the front thereof. Besides, a sensor 230 for detectingthe user's contact may be installed on the front of the smart plug.

The smart plug should not necessarily be implemented in the shape shownin FIG. 2. In other words, the smart plug may have a variety ofapplicable shapes by the structure capable of binding the outlet withthe power cord of the target device. For example, in FIG. 2, theinsertion terminal 210 provided on the rear may be formed on the top,bottom or side, and the binding terminal 220 provided on the front mayalso be formed on the top, bottom or side.

FIG. 3 shows an example of a block configuration of a smart plugaccording to an embodiment of the present disclosure. FIG. 3 shows aconfiguration that can be applied in a case where a smart plug, duringits installation, sets in advance a target device that the smart plugwill monitor.

Referring to FIG. 3, a power measurement unit 310 may measure the amountof power supplied to the target device through a power line. For theamount of power measured by the power measurement unit 310, the amountof power consumption in the target device may be predicted. The powermeasurement unit 310 may provide information about the measured amountof power or power consumption to an event determination unit 330. Theamount of power supplied to the target device may be measured by thepower measurement unit 310 at a preset period. The period may be setconsidering the type and operating characteristics of the target device.The operating characteristics of the target device may include thehabits in which the user uses the target device. For example, if thetarget device is a television, the period in the time zone that the usermainly uses the television may be set shorter compared with the timezone that the user does not mainly use the television.

In one embodiment, the power measurement unit 310 may calculate theamount of power consumption by the supplied current and the suppliedvoltage. In this case, the power measurement unit 310 should be able tomeasure the current and voltage supplied to the target device.

The power measurement unit 310 may analyze the characteristics (e.g.,the power factor) for the change in power consumption based on themeasured amount of power. The power measurement unit 310 may provide theanalysis results to the event determination unit 330. The powermeasurement unit 310 needs to have the ability to process information.In the following description, it will be assumed that information aboutthe amount of power consumption measured by the power measurement unit310 is provided to the event determination unit 330. However, in thecase where the power measurement 310 analyzes the amount of powerconsumption and provides the analysis results to the event determinationunit 330, only the corresponding function may not be handled by theevent determination unit 330, thereby enabling easy application thereof.

A touch sensor unit 320 detects a user's touch, and provides thedetection results to the event determination unit 330. For example, theuser may touch the touch sensor unit 320 for the purpose of theinitialization and the function settings of the smart plug.

The event determination unit 330 may configure a power profile byanalyzing the amount of power consumption provided from the powermeasurement unit 310. The event determination unit 330 may setthresholds for the purpose of monitoring the occurrence of an event inthe target device. The thresholds may be set using the power profile, orbased on the analysis results for the amount of power consumptionprovided from the power measurement unit 310. The number of thresholdsto be set and the setting method may be defined considering thecharacteristics (e.g., the type, brand, capacity, etc.) of the targetdevice.

Representatively, in a case desired to monitor a refrigerator dooropen/closed event, a threshold for recognizing a refrigerator door openevent and a threshold for recognizing a refrigerator door closed eventmay be differently set. In addition, the thresholds to be applied mayneed to be differently set depending on the refrigerator's operationstate corresponding to the open or close of the refrigerator door (e.g.,whether the compressor is operating or not).

An example of setting thresholds for the purpose of monitoring theoccurrence of an event in the event determination unit 330 will bedescribed below with reference to FIGS. 13 and 14.

If the settings for the thresholds are completed, the eventdetermination unit 330 monitors whether a specific event occurs in thetarget device. The occurrence of a specific event may be monitored basedon the analysis result for the amount of power consumption provided bythe power measurement unit 310, and the preset thresholds.

For example, when the analysis result for the amount of powerconsumption provided by the power measurement unit 310 satisfies atleast one threshold that is set for detection of a specific event, theevent determination unit 330 may determine that the specific event hasoccurred in the target device.

The event determination unit 330 may collect information about an eventoccurring in the target device, and manage the collected informationthrough a separate database or report the collected information to theuser through a display or a communication unit 340.

The event determination unit 330 includes an operation algorithm forperforming the above operation. If the smart plug has been produced onlyfor a specific target device, the event determination unit 330 onlyneeds to include an operation algorithm only for the specific targetdevice. For the smart plug, if a target device can be set by the user'ssettings, the event determination unit 330 should include an operationalgorithm for each of various target devices for all the supportabletypes, brands and capacities. In addition, even for the same targetdevice, the event determination unit 330 may include an operationalgorithm for each target event to be monitored.

The event determination unit 330, when a target device is set by theuser, may drive the operation algorithm provided to correspond to theset target device, and monitor the occurrence of an event in the settarget device according to the driven operation algorithm. The eventdetermination unit 330 may include an operation algorithm for eachevent, when there are various events to be detected, for the targetdevice. In this case, when an event to be monitored is set by the user,the event determination unit 330 may drive the operation algorithmprovided to correspond to the set event.

The communication unit 340 may perform communication with the externaldevice by interworking with a predetermined network. For example, thecommunication unit 340 receives information about the type of the targetdevice, which is provided from the external device, provides thereceived information to the event determination unit 330, and transmitsinformation generated by the event determination unit 330 to theexternal device.

FIG. 4 shows another example of a block configuration of a smart plugaccording to an embodiment of the present disclosure.

FIG. 4 shows a configuration that can be applied in a case where a smartplug recognizes what the target device is, by analyzing thecharacteristics of the power consumption measured after itsinstallation. In this case, it is not necessary to install the targetdevice to be monitored, during installation of the smart plug.

To this end, the smart plug shown in FIG. 4 may further include a devicedetermination unit 430 for recognizing a target device, in addition tothe components of the smart plug shown in FIG. 3. Other components arethe same as the components shown in FIG. 3. Therefore, for the samecomponents as those in FIG. 3, a detailed description thereof will beomitted.

Referring to FIG. 4, the device determination unit 430 may monitor theamount of power consumption measured by a power measurement unit 410 fora predetermined time, and analyze the characteristics of the amount ofpower consumption to determine the type, brand and capacity of thetarget device. The device determination unit 430 may include a devicerecognition algorithm for determining a target device.

Operations performed by other components, in addition to the operationof determining a target device by the device determination unit 430, arethe same as those described with reference to FIG. 3.

FIG. 5 shows a block configuration of an event determination unitconstituting a smart plug according to an embodiment of the presentdisclosure.

An event determination unit shown in FIG. 5 includes an adaptivethreshold derivation module (or adaptive threshold module (ATM)) 520,and an event detection module (or event detect module (EDM)) 510.

The adaptive threshold derivation module 520 sets predeterminedthresholds using the result obtained by analyzing the amount of powerconsumption in the target device or the power profile pre-configured tocorrespond to the target device. The thresholds are set for the purposeof monitoring the occurrence of an event in the target device. Thenumber of thresholds to be set and the setting method may be definedconsidering the characteristics (e.g., the type, brand, capacity, etc.)of the target device, and the type of the event.

For example, in a case desired to monitor a refrigerator dooropen/closed event, a threshold for recognizing a refrigerator door openevent and a threshold for recognizing a refrigerator door closed eventare set. In addition, the thresholds to be applied may need to bedifferently set depending on the refrigerator's operation statecorresponding to the open or close of the refrigerator door (e.g.,whether the compressor is operating or not). The thresholds set by theadaptive threshold derivation module 520 are applied to the eventdetection module 510.

The event detection module 510 monitors whether a specific event occursin the target device, based on the thresholds set for the purpose ofmonitoring an event, and the analysis results for the amount of powerconsumption in the target device. For example, if the analysis resultsfor the amount of power consumption in the target device satisfy atleast one threshold set for the detection of a specific event, the eventdetection module 510 determines that the specific event has occurred inthe target device.

FIG. 6 shows a control flow for recognizing occurrence of an event in atarget device by a smart plug according to an embodiment of the presentdisclosure.

Referring to FIG. 6, the smart plug determines a target device,occurrence of an event in which is to be monitored, in operation 610.For example, the target device may be the legacy appliances such as arefrigerator, a television, a washing machine, a vacuum cleaner.

The smart plug may determine a target device by the operator's settings,or may determine a target device based on the monitoring of the powerconsumption. For example, the smart plug may continuously monitor thepower consumption of the target device for a predetermined time, todetermine the target device using the recognized amount of powerconsumption and the power consumption pattern.

In a case where the smart plug is fixed to support a specific targetdevice only, the smart plug does not necessarily require an operationfor determining a target device. In other words, if the smart plug isproduced for only one of the legacy appliances such as a refrigerator, atelevision, a washing machine, a vacuum cleaner, the operation fordetermining a target device in operation 610 may be omitted duringinitial installation of the smart plug.

If the smart plug recognizes the settings or determination of the targetdevice or recognizes the target device, the smart plug loads anoperation algorithm for monitoring the occurrence of an event in thetarget device, in operation 612. For example, the way to recognize anevent may be different depending on the target device. In other words,for each target device, the change in power consumption detected duringthe occurrence of an event, and the power factor may be different, andthresholds to be applied to detect the occurrence of an event may alsobe differently applied. Therefore, in order for the smart plug tomonitor the occurrence of an event in various target devices, it ispreferable for the smart plug to prepare an operation algorithm for eachof all the supportable target devices, and to invoke and use oneoperation algorithm to be applied, among a plurality of operationalgorithms prepared in advance in response to the determination of thetarget device.

In operation 614, the smart plug monitors which event occurs in thetarget device, based on the loaded operation algorithm, and determinesthe event that has occurred, through the monitoring. For example, forthe determination of the event, the smart plug sets thresholds, and thedetermination of the event may be performed based on the set thresholds.An example of a detailed operation thereof is shown n FIG. 7.

Referring to FIG. 7, the smart plug sets at least one threshold for eachoperation state in operation 710. The reason for setting a threshold foreach operation state is because even the same event may have a differentchange in power consumption depending on the operation state that thetarget device operates in.

For example, in the case of a refrigerator, the power signalcharacteristics detected when the refrigerator door is open or closedwhile the compressor is operating may be different from the power signalcharacteristics detected when the refrigerator door is open or closedwhile the compressor is not operating. In other words, the power signalhas the characteristics representing the stronger noise for the powerconsumption while the compressor is operating, compared with while thecompressor is not operating. Therefore, in order to monitor theoccurrence of an event in a target device, the smart plug needs to set adifferent threshold for each operation state.

The smart plug may set one or more thresholds in response to each of thesituation in which a specific operation is being performed in the targetdevice, and the situation in which a specific operation is not beingperformed in the target device. For example, the smart plug may set afirst high threshold and a first low threshold in the situation where aspecific operation by the target device is not being performed, and seta second high threshold and a second low threshold in the situationwhere a specific operation by the target device is being performed.

If the operation state-specific thresholds are set, the smart plugmonitors an event occurring in the target device using the setthresholds in operation 720. For example, in order to detect theoccurrence of an event in the target device, the smart plug may monitorthe consumption pattern of the power supplied to the target device.

By monitoring the change in power consumption, the smart plug maydetermine the event that has occurred, depending on which one of thepreset thresholds is satisfied by the power factor for the powerconsumption. In other words, the smart plug recognizes the occurrence ofa first event, if the power factor for the power consumption existsbetween the first high threshold and the first low threshold. The smartplug may recognize the occurrence of a second event, if the power factorfor the power consumption exists between the second high threshold andthe second low threshold. For example, the first event may be arefrigerator door open event, and the second event may be a refrigeratordoor closed event.

When determining the event that has occurred in the target device, thesmart plug may recognize the operation state of the target devicecorresponding to the determined event in operation 616. The smart plugmay consider that the smart plug has recognized the operation state ofthe target device, by determining the event that has occurred in thetarget device.

Although not shown in FIG. 6, after determining the occurrence of anevent in the target device, the smart plug may provide informationthereon to the operator, or provide the information to the externaldevice such as the sever that manages the status of the target device.

FIG. 8 shows an operation of a subroutine for determining occurrence ofan event in a refrigerator by a smart plug according to an embodiment ofthe present disclosure. In FIG. 8, it is assumed that the smart plugshould monitor the occurrence of an event in the refrigerator.Recognizing that the target device is a refrigerator may be performed bythe method such as user registration or automatic device recognition (oreasy set up).

Referring to FIG. 8, the smart plug may perform the procedure (or thethreshold setting procedure (operations 812 to 820)) for setting aplurality of thresholds or the procedure (or the event detectionprocedure (operation 822) for detecting an event, by the determinationresult in operation 810.

In one embodiment, the smart plug determines in operation 810 whetherall the thresholds to be used to detect the occurrence of an event inthe refrigerator are set. The thresholds to be used to detect theoccurrence of an event should be defined considering the operation modeof the refrigerator in which an event may occur. A detailed descriptionthereof will be given in the following description.

For example, the event that can occur in the refrigerator may beidentified in an example of the power profile shown in FIG. 12. Thepower profile shown in FIG. 12 has been prepared by monitoring the powerconsumption of the refrigerator for 24 hours.

Referring to the power profile shown in FIG. 12, it can be noted thatthe power consumption in the refrigerator is roughly divided into powerconsumption by the compressor operation, power consumption by thedefroster operation, and power consumption by the other operations. Inother words, the operation state in the refrigerator mainly includes thepresence/absence of the periodical compressor operation and thepresence/absence of the defroster operation. Aside from that, the powerprofile of the refrigerator may vary depending on the type of therefrigerator that is classified into the inverter type refrigerator,constant speed-type refrigerator, and the linear-type refrigerator. FIG.12 shows a 24-hour operation profile for the constant speed-typerefrigerator.

The circled parts in the enlarged graph shown at the bottom of FIG. 12represent the power signal characteristics in the case where a door openevent has occurred. Since it is general that the interior lights areturned on as soon as the refrigerator's door is open, a change in thepower consumption occurs. The fact to be noted here is that the size ortype of the lights may vary depending on the type and capacity of therefrigerator, causing a change (10 to 80 W) in the power consumption.

For example, assuming that the noise is 20 W when the compressor isoperating in the refrigerator where the change in the lighting power is80 W, it is possible to design a smart plug so as to determine theevent, taking this into consideration. In this case, in the refrigeratorwhere the change in the lighting power is 10 W, it may be difficult todetect the change of 10 W in the lighting power due to the noise.

In this way, it is not easy to determine an event whose power change isfine. Therefore, the smart plug should derive a reference value fordetermining the occurrence/non-occurrence of a door open event and adoor closed event of the refrigerator installed in the home. Forexample, in order to determine the door open event, a total of twothresholds (e.g., the positive high threshold (or the first highthreshold) and the positive low threshold (or the first low threshold))are required, and in order to determined the door closed event, a totalof two thresholds (e.g., the negative high threshold (or the second highthreshold) and the negative low threshold (or the second low threshold))are required.

In order to set the threshold that has not been set, the smart plugdetermines in operation 812 whether the compressor is operating. Thesmart plug may determine whether the compressor of the refrigerator isoperating or not, based on the power consumption of the refrigerator.The reason is because the refrigerator has a big difference in theamount of power that is consumed when the compressor is operating, andwhen the compressor is not operating.

When the compressor is not operating, the smart plug determines inoperation 818 whether the reason that all the thresholds have not beenset is because the high threshold has not been set. In other words, thesmart plug determines the presence/absence of the settings of all thehigh thresholds (e.g., the positive high threshold (or the first highthreshold) and the negative high threshold (or the second highthreshold)) for detecting an event. When the settings of all the highthresholds do not exist, the smart plug sets the high thresholds that donot exist, in operation 820.

When the compressor is operating, the smart plug determines in operation814 whether the reason that all the thresholds have not been set isbecause the low threshold has not been set. In other words, the smartplug determines the presence/absence of the settings of all the lowthresholds (e.g., the positive low threshold (or the first lowthreshold) and the negative low threshold (or the second low threshold))for detecting an event. When the settings of all the low thresholds donot exist, the smart plug sets the low thresholds that do not exist, inoperation 816.

FIG. 13 shows an example of setting a first high threshold (a circlednumber 1) and a second high threshold (a circled number 2) when acompressor is not operating, according to an embodiment of the presentdisclosure.

In FIG. 13, the first graph is a graph (hereinafter, referred to as a“first real power graph”) showing a change in the real power over thetime, and the second graph is a graph (hereinafter, referred to as a“first power factor graph”) showing a change in the power factor overthe time.

FIG. 14 shows an example of setting a first low threshold (a circlednumber 3) and a second low threshold (a circled number 4) when acompressor is operating, according to an embodiment of the presentdisclosure.

In FIG. 14, the first graph is a graph (hereinafter, referred to as a“second real power graph”) showing a change in the real power over thetime, and the second graph is a graph (hereinafter, referred to as a“second power factor graph”) showing a change in the power factor overthe time.

Taking a close look at the first and second power factor graphs shown inFIGS. 13 and 14, it is possible to determine the door open event thatoccurs when the compressor is operating and the door open event thatoccurs when the compressor is not operating, based on the change in thepower factor. The reason is because it could be noted through theexperiments that the change in real power is different for each device,but the power factor not only falls within the range of 0 to 1, but alsoexceeds a minimum of 0.4 during any lighting operation (a compressornon-operation condition).

However, it can be noted that even if the door open event occurs, thepower factor is different when the compressor is operating and when thecompressor is not operating. This is because the principle ofsuperposition is not applied to the power factor. Therefore, in order todetermine the events for the open and close of the refrigerator door,two positive thresholds and two negative thresholds should be set.

Referring to FIG. 13, an operation of setting thresholds when thecompressor is not operating will be described. The time, at which thedoor open event and the door closed event occur, is calculated, based onthe change in the power factor when the compressor is not operating.Since the change in real power may vary depending on the case, apositive high threshold {circle around (1)} and a negative highthreshold {circle around (2)} are derived by utilizing the differencebetween the real power P and the bias P_bias of the real power duringoccurrence of an event.

For example, P_bias may be obtained by an average of the real power for10 minutes, when the power factor PF is less than 0.4 and the real powerP is less than 90 W. The real power is calculated, when the power factoris greater than 0.4 and the real power is less than 90 W for one or moreseconds.

After the real power P and the bias P_bias of the real power arecalculated as described above, a positive high threshold {circle around(1)} and a negative high threshold 2 are determined by the value that isabout 1.5 times the value of (P−P_bias). In other words, the positivehigh threshold 1 is determined by giving the positive sign to the valuethat is about 1.5 times the value of (P−P_bias), and the negative highthreshold {circle around (2)} is determined by giving the negative signto the value that is about 1.5 times the value of (P−P_bias).

Referring to FIG. 14, an operation of setting thresholds when thecompressor is operating will be described. A lot of noise is generatedwhen the compressor is operating. Therefore, in order to determine theoccurrence of an event while the compressor is operating, the positiveand negative low thresholds should be set so as to reduce the wrongdetermination.

The case of FIG. 14 corresponds to the case where a lot of noise is notgenerated. However, in the case where a lot of noise is generated, a wayto obtain the positive low threshold and the negative low threshold maybe the same. First, the compressor's operation is determined by the realpower, and the noise in the positive zone and the noise in the negativezone are stored for about 10 minutes.

Thereafter, the stored positive noises and negative noises are arrangedor classified in the descending order of their absolute values, andthen, the maximum value is obtained after removing about 5% of theoutlier. Generally, it is known that utilizing the maximum value or themedium value after removing the outlier is most favorable. The outliermay include on-peak by the compressor's operation and the power changedue to the door open.

The value corresponding to about 2 times the maximum value among thevalues except for the above outlier is calculated, and a positive lowthreshold {circle around (3)} and a negative low threshold {circlearound (4)} are determined by the calculated value. In other words, thepositive low threshold {circle around (3)} is determined by giving thepositive sign to the calculated value, and the negative low threshold{circle around (4)} is determined by giving the negative sign to thecalculated value.

By the above operation, the smart plug may obtain a total of fourthresholds consisting of the positive high threshold {circle around(1)}, the negative high threshold {circle around (2)}, the positive lowthreshold {circle around (3)}, and the negative low threshold {circlearound (4)}. The obtained four thresholds are set in the smart plug, tomake it possible to determine the occurrence of the event due to theopen and close of the refrigerator door.

Meanwhile, as in the embodiment proposed above, a value corresponding toa small change in power is mainly used in determining individual events(detailed operations) of appliances, and this value is relatively highin terms of the dependence on the model and the capacity of a specificdevice. Given this, an adaptive algorithm is needed in determining allthe individual events.

If it is determined that all the thresholds have been set, the smartplug monitors in operation 822 whether a specific event occurs in therefrigerator, using the set thresholds. The smart plug may detect theoccurrence of an event in the refrigerator based on the power signalcharacteristics of the power supplied to the refrigerator and the setthresholds.

For example, the power signal characteristics may be defined using thereal power and the power factor. However, it could be noted through theexperiments that the change in real power is different for each device,but the power factor not only falls within the range of 0 to 1, but alsoexceeds a minimum of 0.4 during any lighting operation (a compressornon-operation condition). Therefore, it will be preferable to use thepower factor as the power signal characteristics for detecting theoccurrence of an event in the refrigerator.

The power factor may be define by the ratio of the reap power [P] to theapparent power [S] in the alternating current (AC) circuit. The reappower [P] and the apparent power [S] are the same in the AC circuit towhich only the pure storage is connected. However, if the AC circuitincludes a reactance component defined as an inductance and acapacitance, the apparent power is greater than the real power (oreffective power) appearing as heat, light, and radio waves. This extrapower is reactive power [Q]. Mathematically, the reactive power [Q] isexpressed as an imaginary number.

FIG. 9 shows a relationship among real power [P], reactive power [Q] andapparent power [S]. In other words, it has a relationship of “S=P+jQ”.Here, an angle Θ between the real power [P] and the apparent power [S]may be regarded as a phase difference between a voltage waveform and acurrent waveform.

FIG. 10 shows an example in which there is no phase difference between avoltage waveform and a current waveform, and FIG. 11 shows an example inwhich a phase difference between a voltage waveform and a currentwaveform is 90°.

As shown in FIG. 10, it can be noted that the fact that there is nophase difference between a voltage waveform and a current waveformindicates that the AC circuit is an AC circuit to which only theresistive load is connected. In this case, the power factor is 1. Asshown in FIG. 11, in the case where the phase difference between avoltage waveform and a current waveform is 90°, the power factor is 0.

The fact that the power factor is 0 means that the current flows but theaverage power is 0. The reason why the phase difference of 90° occurs inthe voltage waveform and the current waveform is because of thereactance component constituting the AC circuit. For example, if the ACcircuit has an inductive reactance component, the current falls behindthe voltage by a maximum of 90° (or ¼ cycles). However, if the ACcircuit has a capacitive reactance component, the current may have aphase preceding that of voltage by a maximum of 90°.

As described above, it can be noted that since the power factor can berepresented as a ratio (cosine theta) of the apparent power to the realpower, the range of its value is limited to 0 through 1. This is thevalue of the range that is given regardless of the power value, and ifthe power consumption in one device is monitored by like the smart plug,that can be a useful means for detecting a change in the internal stateof the device.

For example, in the case of the compressor operation, the defrosteroperation and the lighting operation during the refrigerator operation,since all the other components are included, the change in power factoris natural when there is a change in the state of the device.

However, in the case of the power factor, the principle of superpositionis not applied when the internal components operate at the same time. Inother words, since all the reactance components are considered andreflected in the phase difference, they may be obsolete if the correctpoints are not determined. For this reason, only the power factor givenwhen the refrigerator's compressor and defroster do not operate has beenconsidered in the foregoing description.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The invention claimed is:
 1. A smart plug device installed on a powersupply route between a power supply and a target device to detect anevent occurring in the target device, the smart plug device comprising:a power measurement unit; and an event determination unit configured to:set at least one high threshold and at least one low threshold based onwhether the target device is operating in a specific operation mode,obtain a power supplied to the target device via the power measurementunit, identify a power signal characteristic indicating a changecharacteristic of the power that is caused by an occurrence of the eventbased on the power before the event occurs in the target device, andidentify the occurrence or non-occurrence of the event in the targetdevice based on whether the power signal characteristic satisfies atleast one of the set at least one high threshold or the set at least onelow threshold.
 2. The smart plug device of claim 1, wherein the powersignal characteristic represents a power factor defining a ratio of realpower to apparent power in an alternating current circuit.
 3. The smartplug device of claim 1, wherein the power signal characteristicrepresents a power factor corresponding to a phase difference between avoltage waveform and a current waveform of the power that is measured bythe power measurement unit.
 4. The smart plug device of claim 3, whereinthe event determination unit is further configured to: set at least onehigh threshold and at least one low threshold based on whether thetarget device is operating in the specific operation mode, and identifythe occurrence or non-occurrence of the event in the target devicedepending on whether the power signal characteristic satisfies at leastone of the set at least one high threshold or the set at least one lowthreshold.
 5. The smart plug device of claim 1, wherein the eventdetermination unit comprises: an adaptive threshold derivation moduleconfigured to: set one high threshold and one low threshold bycollecting a noise value included in the power that is measured by thepower measurement unit when the target device is operating in thespecific operation mode, and set one high threshold and one lowthreshold using a power factor, real power, and a bias value for thepower that is measured by the power measurement unit when the targetdevice is not operating in the specific operation mode; and an eventdetection module configured to: compare a power factor valuecorresponding to the power signal characteristic with two highthresholds and two low thresholds set by the adaptive thresholdderivation module, and identify the occurrence or non-occurrence of theevent in the target device based on a result of the comparison.
 6. Thesmart plug device of claim 5, wherein, when the specific operation modecomprises an operation mode in which a compressor is operating in arefrigerator, the two high thresholds are set to predict an occurrenceof a refrigerator door open event, and the two low thresholds are set topredict an occurrence of a refrigerator door closed event.
 7. The smartplug device of claim 6, wherein the event detection module is furtherconfigured to: identify the occurrence of the refrigerator door openevent when the power factor value corresponding to the power signalcharacteristic is within a range formed by the two high thresholds, andidentify the occurrence of the refrigerator door closed event when thepower factor value corresponding to the power signal characteristic iswithin a range formed by the two low thresholds.
 8. The smart plugdevice of claim 1, further comprising: a determiner determination unitconfigured to determine a type, a brand, and a capacity of the targetdevice, wherein the event occurring in the target device is determinedbased on the type of the target device.
 9. The smart plug device ofclaim 1, wherein the at least one high threshold and the at least onelow threshold are set based on characteristics of the target device anda type of the event.
 10. A method for detecting an event occurring in atarget device by a smart plug device installed on a power supply routebetween a power supply and the target device, the method comprising:setting at least one high threshold and at least one low threshold basedon whether the target device is operating in a specific operation mode;obtaining a power supplied to the target device via a power measurementunit of the smart plug device; identifying a power signal characteristicindicating a change characteristic of the power caused by an occurrenceof the event based on the power before the event occurs in the targetdevice; and identifying the occurrence or non-occurrence of the event inthe target device depending on whether the power signal characteristicsatisfies at least one of the set at least one high threshold or the setat least one low threshold.
 11. The method of claim 10, wherein thepower signal characteristic represents a power factor defining a ratioof real power to apparent power in an alternating current circuit. 12.The method of claim 10, wherein the power signal characteristicrepresents a power factor corresponding to a phase difference between avoltage waveform and a current waveform of the power.
 13. The method ofclaim 12, wherein the identifying of the event comprises: setting atleast one high threshold and at least one low threshold based on whetherthe target device is operating in the specific operation mode; andidentifying the occurrence or non-occurrence of the event in the targetdevice depending on whether the power signal characteristic satisfies atleast one of the set at least one high threshold or the set at least onelow threshold.
 14. The method of claim 10, wherein the settingcomprises: setting one high threshold and one low threshold bycollecting a noise value included in the power when the target device isoperating in the specific operation mode; and setting one high thresholdand one low threshold using a power factor, real power, and a bias valuefor the power when the target device is not operating in the specificoperation mode.
 15. The method of claim 14, wherein the identifying ofthe occurrence or non-occurrence of the event comprises: comparing apower factor value corresponding to the power signal characteristic withtwo high thresholds and two low thresholds; and identifying that theevent has occurred in the target device based on a result of thecomparison.
 16. The method of claim 15, wherein, when the specificoperation mode comprises an operation mode in which a compressor isoperating in a refrigerator, the two high thresholds are set to predictan occurrence of a refrigerator door open event, and the two lowthresholds are set to predict an occurrence of a refrigerator doorclosed event.
 17. The method of claim 16, wherein the identifying of theoccurrence or non-occurrence of the event comprises: identifying theoccurrence of the refrigerator door open event when the power factorvalue corresponding to the power signal characteristic is within a rangeformed by the two high thresholds; and identifying the occurrence of therefrigerator door closed event when the power factor value correspondingto the power signal characteristic is within a range formed by the twolow thresholds.
 18. The method of claim 10, further comprising:identifying a type, a brand, and a capacity of the target device,wherein the event occurring in the target device is determined based onthe type of the target device.